The 34-year-old Duchess of Cambridge served as the Guest Editor of the Huffington Post on Wednesday, and took the opportunity to write about the importance of improving and understanding the mental health of young children -- a cause she has previously advocated for. Specifically, she promoted the mental health charity, Young Minds Matter -- a new series where issues and work around the mental health of young children will be explored -- which launched on Wednesday.

"Shortly after I got married, I started working with charities helping those affected by issues such as addiction, family breakdown and vulnerable children," Middleton explained. " ... What I did not expect was to see that time and time again, the issues that led people to addiction and destructive decision making seemed to almost always stem from unresolved childhood challenges."

"The mental health of our children must be seen as every bit as important as their physical health," she continued. "For too long we have been embarrassed to admit when our children need emotional or psychiatric help, worried that the stigma associated with these problems would be detrimental to their futures."

Middleton said that she and Prince William would not hesitate to seek help for their own children -- 2-year-old Prince George and 9-month-old Princess Charlotte -- should they need it.

"We hope to encourage George and Charlotte to speak about their feelings, and to give them the tools and sensitivity to be supportive peers to their friends as they get older," she wrote. "We know there is no shame in a young child struggling with their emotions or suffering from a mental illness."

"Parenting is hard enough without letting prejudices stop us from asking for the help we need for ourselves and our children."

Middleton also called on schools and communities to help when families are short on time or money.

"Together, we have the chance to make a real difference for an entire generation of young children," she wrote.

And the Duchess already has one big supporter in her corner-- first lady Michelle Obama, who wrote her own blog post on Huffington Post in support of Middleton.

"Her Royal Highness The Duchess of Cambridge has been a passionate voice on so many important issues, and I'm grateful that she is using her day as Guest Editor to shine a bright light on mental health, particularly children's mental health, and on the tens of millions of people who suffer in silence," Obama wrote, also advocating for more mental health initiatives for veterans.

"We need to learn to identify the signs of mental-health issues," Obama added. "We need to have the courage to reach out and have tough conversations with our friends and family members -- and get help ourselves when we need it. And we need to recognize that our mental health is just as important as our physical health, and start treating it that way."